Automatic cut-off valve



June 14, 1938. w. s. DIEHL 2,120,242

AUTOMATIC CUT-OFF VALVE Filed Aug. 12, 19:56

INVENTOR WALTER S. D/EHL ATTORNEY Patented une. 14,1938

UNITED STATES PATENT OFFICE (Granted under the act of March- 3, 1883, as amended April 30, 1928; 3'10 0. G. 157)- invention relates to improvements in automatic cut-oft valves to prevent the loss of the fluid under pressure, in the event of a rupture in the system. An important object of this invention is to provide an automatic cut-ofl valve, in a system supplying fluid under pressure, which may be a means for rearming or resetting the valve when the operator desires to again put the fluid sysl5 tem into commission.

Other objects and advantages of the invention will be apparent during the. course of the following description.

In the drawing, forming apart of this specification, and in which like numerals are .employed to designate like parts throughout the same,

Fig. 1 is a cut-away side elevation of the as sembled valve; r

Fig. 2 is a modification of the plunger with a pivoted toggle rather than a sliding toggle;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a side elevation of the valve plunger showing it drilled with several longitudinal holes rather 'than longitudinal slots or grooves; and

Fig. 5 is an end elevation of Fig. 4.

In the drawing, wherein for the purpose of illustration, is shown a preferred embodiment of my invention, the number 6 designates the metal valve body with a flanged inlet opening 1 and flanged outlet opening 8. Contained within the valve body is a plunger 9 provided with longitudinal grooves or slots Ill, an annular groove II, and a valve member I2. Resting Within the annular groove H is a toggle 13, which toggle is securely held in place by a grooved plunger M, which is slidably mounted in a cylindrical boss I4 formed integrally with the valve body 6. A plunger spring I5 is also disposed within the boss l4 between the plunger l4 and an adjusting nut l6, which is threaded into the upper end of the boss ii. The upper endof the boss i4 is closed by a cap screw 11.

The valve member I2 is machined to seat on a valve seat l8 surrounding an opening l8. A reseating spindle is is manually operable through a stufling box 20 by a knob 2| for the purpose of rearming the valve member l2. A raised shoulder 22 prevents the spindle l9 from being withdrawn from the stufling box 20.

I any rupture take place in the system on the out- Fig, 2 shows a toggle l3 attached to the plunger ll by'a pivot 23.

Fig. 4 and Fig. 5 show the longitudinal 'slots or grooves III in the plunger 9 replaced by longitudinal holes l0.- 5

The operation of the automatic cut-oil valve is as follows:

Before putting the valve 6 into operation the plunger spring I5 is set ata predetermined tension by means of adjusting nut l6 so that the 10 toggle l3 will maintain the plunger 9 in its normal position, as shown in Fig, 1. The valve is armedor cocked by pushing'spindle l9 into engagement with valve face I2 and continuing this movement until the plunger 9 is returned to its normal 15 position. With the valve 6 so armed, the fluid under pressure flows into the'valve 6, the inlet 1, thence through the longitudinal slots, grooves or holes III of plunger 9 and through the valve opening I8, and thence through outlet 8. Should let side of the automatic cut-out valve the pressure on this side of the valve body 6 will immediately drop to zero, as will the pressure on the downstream side of the plunger 9. The pressure which is acting on the upstream face of plunger 9 will be exerted on it and will overcome the pressure exerted on the plunger 9 by the toggle l3 and will cause the plunger 9 to travel along the cylinder of the valve body 6 and force the valve member l2 intoengagement with the valve seat l8, thus sealing it to prevent any further flow of the fluid through the outlet 8. The size of the valve body 6 and plunger 9 depends upon the'pressure drop required to trip toggle i3. The size of the 35 toggle l3 depends upon the tripping load diiferential, which is dependent on the maximum rate of normal flow throughthe valve body 6, and the viscosity of the fluid. An approximate size may readily be calculated from the equations of lhy- 40 drodynamics, and the exact relations may be found by adjusting, the tripping load on the toggle'spring. v It is understood that the form of my invention, herewith shown and described, is to be taken 5 as a preferred example of same, and the various changes in the shape, size and arrangement of partsmay be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims. I

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental t purposes without the paymentof any royalties thereon or therefor. 55

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. A valve operated by diflerential fiuid pres sure comprising a cylindrical fluid passage with an orifice in the downstream end, a grooved piston slidably fitted in said cylindrical passage and carrying a needle device on its downstream end, said needle device ccaxially registering with said downstream orifice a toggle device for holding said piston and appendage selectively away from or against said orifice, and a rearming device for setting said piston in a valve-open position against the toggle action tending to keep said piston in a valve-closed position.

2. A valve operated by differential fluid pressure comprising a cylindrical fluid passage with an orifice in the downstream end, a perforated piston slidably fitted in said cylindrical passage and carrying a needle device on its downstream end, said needle device coaxially registering with said downstream orifice, a toggle device for holding said piston and appendage selectively away from or against said orifice, and a rearming device for setting said piston in a valve-open position against the toggle action tending to keep said piston in a valve-open position against the toggle action tending to keep said piston in a valve-closed position.

3. A valve operated by difi'erential pressure comprising a cylindrical fluid passage with scored walls and an orifice in the downstream end, a piston slidably' fitted in said cylindrical passage and carrying a needle device on its downstream end, said needle device coaxially registering with said downstream orifice, a toggle device for holding said piston and appendage selectively away from or against said orifice, and a rearming device for setting said piston in a valve-open 'position against the toggle action tending to keep said piston in a valve-closed position.

WALTER s. DIEHL. 

